This blog is a lab notebook for my work with the Reprap open source 3D printing undertaking.

Monday, February 01, 2010

A stepper controller for the Delta Robot

Some time ago, Nophead {Chris Palmer} suggested that I use microstepping instead of gearing to get the resolution that I need in using the herringbone rack and pinion with the Delta Robot kinematics. I had hesitated because doing so got me into the surface mount Allegro controller chips. I could have used the standard Reprap controller board except that it is incompatable with my Pic-based controller.

The A4983 is somewhat different than the A3977 that is standard in Reprap electronics in two ways. Foremost, the A4983 can handle a maximum current of only 2 amps instead of the A3977's 2.5. I don't find this compelling because in practice Repraps rarely require more than 1 amp in any case.

The winner for me is that the A4983 controller allows for microstepping down to 1/16 compared to the A3977's 1/8. While the A3977's microstepping is more than adequate for conventional Reprap machines I can use the extra resolution with the Delta Robot.